/Engine/Source/Runtime/Engine/Classes/Engine/NetDriver.h
Explicitly sets the ReplicationDriver instance (you instantiate it and initialize it). Shouldn't be done during gameplay: ok to do in GameMode startup or via console commands for testing. Existing ReplicationDriver (if set) is destroyed when this is called.
void SetReplicationDriver ( [UReplicationDriver](API\Runtime\Engine\Engine\UReplicationDriver) * NewReplicationManager )